A fast growing market both in civilian and military business is geographical information systems. Knowledge about geographical conditions forms a fundamental decision support to companies, authorities and in the military. The geographical information comprises digital maps having superposed information layers such as infrastructure, terrain type and different types of objects. It is a time consuming process to form two dimensional maps comprising capturing images of the terrain from an aircraft and post-processing of the captured images. It is an even more time consuming process to form three dimensional maps from captured images or range data sets of the terrain/infrastructure. There are available today different methods such as photogrammetric methods with manual stereo-processing and laser scanning. These methods require time-consuming post-processing. Therefore, the formation of three-dimensional maps becomes expensive. As a consequence thereof, updates of the maps are made with a low updating frequency.
EP 1 657 927 discloses image-based movement tracking of a number of objects in a particular area based on stereo-processing. In this application, cameras are mounted in fixed and known positions. Therefore, matching between images captured by the different cameras is less time consuming than in the case of moving cameras.
One object of the present invention is to provide an improved way of providing three dimensional map representations.